1. Field of the Invention
The invention relates to a strain-sensitive resistor comprising a resistance layer arranged on a support element and an electromechanical transducer produced with this resistor.
2. Description of the Prior Art
German patent application 197 47 001.7 discloses a strain-sensitive resistor in which the resistor is arranged on a shaft constructed as a support element. The shaft is subjected to mechanical loading, the surface strain resulting from this being picked off by the strain-sensitive resistor arranged on this shaft without any intermediate support. The resistance layer is applied to the shaft in the form of a resistive paste, using a printing technique, and intimately connected to said shaft after a heat treatment.
In the event of torsion of the shaft, two main strains at 45° are formed on the surface of the shaft. These strains are evaluated in order to determine the torque. In this case, the main strains have the same magnitude but the opposite sign.
The thick-film resistance pastes used have positive strain factors (K factors) both for the longitudinal and for the transverse strains, for which reason only the difference of these two factors can be used to determine the effective resistance change. The signal voltages registered at the torque sensor are therefore very low and must be amplified by a comprehensive electrical arrangement, as a result of which the influence of interference on the small measured signal is increased.